Hi Elektronauts,
I have a Digitakt that was modded with a third party battery pack. Prior to coming to me it stopped turning on. No screen. No lights.
I desoldered the battery mod and tested the power points on the board and they all return the correct values.
Any advice on troubleshooting steps I could try to find the issue
I’m hoping it’s not a dead chip or flash ram situation.
Thanks
Rumble
start with simple, go from there. did you verify the switch itself is not the issue? any evidence the battery leaked? the dc connector jack doesn’t have a bent or broken tab inside?
when you say they return the correct values, you’re testing with it plugged in or are you just checking continuity? testing with live power is risky.
Started with the simple.
Measured the power out of the supply. 12v’s correct
Checked the switch. No problem.
Measured the test points on the board while under load. All return values as indicated on the board.
Could not detect any excess heat on the chips while testing power rails.
did you sniff around the PCB for any indication of burnt components? my nose often leads me to the vicinity of the problem. what is the manufacture date on the bottom of the device? are you doing this with the top and bottom still connected by the ribbon cables or have you separated them and detached the faceplate?
if you haven’t already, I would consider completely removing both ribbon cables and make sure that all matching pin sockets on the molex connectors side to side are showing continuity to insure none of the lanes are broken.
Haven’t been able to smell any burning. I’m doing this with the boards removed and suspended in my PCB jig. I took the measurements with the control board disconnected and then connected.
I tested the continuity of the ribbon connectors are they are fine.
There is a copyright date of 2017 on the mainboard with CPU4101E written next to it.
Thanks for your assistance.
wish I could do more for you, I’ll have to think about it a bit. unfortunately, elektron keeps service info under lock and key and you can’t even find schematics for discontinued products let alone current ones.
hopefully this can be diagnosed and resolved, but as I understand it the device was already out of service when you received it so you’re really trying to pick up from a point of the complete unknown with very few clues to work from.
from what I remember a replacement PCB is around $125USD plus $12 shipping directly from elektron but you’d need to confirm that with support via a service ticket because my information on that is a couple of years old. That’s to say if the headache becomes too grand, there is a way you can buy away your woes.
anyhow, I’ll give it some more thought when I have a minute. for what it’s worth though, if you confirm on the bottom of the chassis box the mfg date, your PCB date indicates that it’s probably one of the early DT’s because there are a couple of board revisions and in that, the problem could even be unrelated to the battery. It’s easy to assume the battery was the issue, but it’s not 100% definitive that that was the cause.
the easiest thing to do now, is if you know someone else who has a DT, convince them to let you open up their machine and try your top UI board with their lower logic board and if your upper PCB functions as it should then you can definitively localize the issue to the bottom, because as it stands, your testing is inconclusive and right now you’re trying to cover twice the real estate.
even if you intend to continue diagnosis on a point to point basis, it sure would be a lot easier to cut the search area in half.
I was thinking the same thing. Have been speaking with a supplier of Digitakt parts locally and he can sell me a replacement main board. Perhaps he could test the control board for me.
I would highly recommend, if at all possible, you try to do that.
Did some further troubleshooting on the control board. Was unable to see 3.3v at J3. Then noticed the screen was getting really hot. I removed it and retested. The MCF chip beneath the screen was searing hot. I removed it and all the shorts disappeared.
Have ordered a replacement control board from a local supplier.
I’m glad you traced it without having to fully go through both boards, the problem being obscured by the screen was probably throwing you off the trail in the first place. I hope this clears the issue entirely and you can get it to boot up after replacement. Sounds pretty clear that the prevalent issue was the chip though.
I hope you can update this and let us know what happened, good resource material for future searches. People run into all kinds of issues and come here looking for answers. Nice work!
I fitted the replacement control board today and the unit booted up. It looks to be working correctly I can go through all the settings and samples.
When I ran test mode it came up with zero errors but when I press button 1 it displays a white screen. Button 2 it displays a black screen. Is this normal?
All other keys and encoders return the correct name for the key pressed.
Yes ! 
Screen check buttons for all Elektrons I know.
Glad you got it working and yep, like sezare56 said, it’s just a screen check to test for dead pixels. Congratulations and hope that you get to finally enjoy it!
Random question are the volume pots on Octatrack Mk2 and Digitakt the same part?
I don’t know this for a fact but they should be, probably an alpha 10k audio taper. Do you need a volume pot?
I just got hold of a used Octatrack MK2 and the volume knob works but is super wobbly. Looking to replace it at some stage as was wondering if its worth de-soldering the pot from the old Digitakt control board to reuse the pot.
Is it wobbly like the claws on the pcb side of the potentiometer body are starting to bend and it’s forcing back casing out so it’s making the shaft wobble? Or is it the kind of wobble that you get when you spray it with contact cleaner and all the grease washes out? Like does it still turn with some resistance but is wobbly? Or is it more like wobble and also it’s super fast going from minimum to max as if there’s no grease in the pot body?
I mean yes, probably worth saving the pot and possibly the encoders as those are likely the same, but if you can tell the claws are bent you might be able to take care of that with a small plier just to make the rear body captive again, if you’re careful at least I would think you can.
There is still resistance in the knob but it wobbles. Not the shaft but the body of the pot. Hard to fully diagnose with out taking apart the Octa.
I’m just thinking that it’s probably like the one on the digi, where there are alignment pegs on top and bottom, but the same metal chassis that grounds the pot chassis/bushing to the pcb also has retaining claws that hold the pot body to the metal chassis. I could be wrong but I think if this is the problem (the body is coming loose from the metal chassis) those claws / clips can be massaged back into place. You may be able to do that without removing the pot. You’d just have to be careful not to overcompress it and crush the pot so that the shaft / contact wiper has no room for travel.
You are correct though, you’ll have to inspect a little further.
